The present invention relates to a process and system for processing fruit juice and to a juice deacidification process and system utilizing ion-exchange resin columns. More particularly, the invention provides operating conditions which enhance deacidified product quality.
Juice products are highly popular with consumers due to both their taste and their nutritional value. However, some fruit juices, such as those from citrus fruits, can have a level of acidity that makes them disagreeable to persons with sensitive stomachs.
Numerous individuals have been known to experience negative effects upon ingesting different foods. A true food allergy occurs when the immune system of the individual overreacts to certain proteins in food. It is believed that hundreds of food ingredients can provoke an allergic reaction. Typical foods in this regard are nuts, peanuts, milk, eggs, fish, shellfish, soybeans and wheat. Foods such as these can lead to symptoms including nausea, hives, skin rash, nasal congestion, wheezing, and the like. However, most unpleasant reactions to food are caused not by allergies but by intolerances, which tend to be less severe than true food allergies. Typical in this regard are lactose intolerance, sulfite intolerance and intolerance to monosodium glutamate, red wine, chocolate and food coloring agents. Another intolerance of some frequency is manifested by gastral distress and/or digestive difficulties which certain individuals experience shortly after ingesting orange juice products.
In some circles, it is generally assumed that the relatively high acidity of orange juice products is a primary contributor to these negative or unpleasant experiences with orange juice products for a small percentage of the population. For example, Kligerman et al U.S. Pat. Nos. 5,665,415 and 5,869,119, incorporated hereinto by reference, suggest that acidic foods or beverages such as coffee and other beverages can be combined with calcium glycerophosphate so as to raise the pH of the food or beverage by at least 0.5 pH units, such as to a pH of greater than 5.4, which typically is pH higher than desirable for superior tasting orange juice. This pH adjustment is said to reduce the tendency of the food or beverage to cause heartburn and other esophageal and/or gastrointestinal distress. This approach generally follows the conventional wisdom that ingesting antacids treats heartburn by helping to neutralize stomach acid. This approach suggests, in general, raising the pH of the food or beverage to well above 5.
Processes for deacidifying citrus juice have been known since the 1960s, and commercially-viable deacidification processes using anionic ion exchange for acid reduction of citrus fruit juices were known by 1980. However, such processing was used for deacidifying juice made from concentrate, which has a standard of identity (SOI) that permits a great range of flexibility in the processing steps with respect to the dilution and blending of the juice product.
Since that time, “not from concentrate” or NFC juices have become very popular with consumers because of their “fresh-squeezed” taste. These NFC juices must meet their own SOI criteria. Among these criteria is the avoidance of a final juice product which has water added characteristics. Other criteria typically include brix minimums and brix-to-acid ratio minimums.
For example the US Food and Drug Administration sets a standard for juices such as orange juice, including brix minimums. In this regard 21 CFR Section 146.140, incorporated by reference hereinto, states that finished pasteurized orange juice is to contain not less than 10.5 percent by weight of orange juice soluble solids, exclusive of the solids of any added sweetening ingredients. This FDA regulation further states that the ratio of brix to grams of citric acid per 100 ml of juice is not less than 10 to 1. The juice industry recognizes these criteria for pasteurized orange juice or single strength orange juice as applying to NFC orange juice. It will be understood that these SOI criteria are used herein with respect to NFC orange juice or pasteurized single strength orange juice. This same concept of SOI criteria applies as well to other pasteurized single strength juices.
While it is anticipated that there would be a significant market for a low acid NFC orange juice, deacidification processes utilizing ion-exchange resin columns can easily result in the processed juice being diluted. This is particularly true if the ion-exchange column is designed to operate with a water/juice interface or a “water dome” in the head space of the column above the resin bed. Such water dilution of the processed juice is unacceptable for NFC juices because the standard of identity (“SOI”) of the juice is compromised. This is an issue raised by deacidification.
Another issue which can be raised by certain deacidified citrus juice products is not a concern for non-deacidified citrus juices and the like. The low pH of acid foods does not favor the growth of certain pathogenic microorganisms such as Clostridium botulinum. Since these microorganisms are more likely to grow at a pH above 4.6, low acid or deacidified foods may require a more aggressive heat treatment to prevent microbial growth and spoilage. Non-deacidified citrus juices including orange juice and grapefruit juice traditionally are categorized as acid food, which require a less severe heat treatment (pasteurization) to prevent microbial growth. Technically, to meet the requirement of acid food, the pH of the deacidified juice should be less than 4.6 during processing. If the pH is greater than this, an aggressive treatment to prevent microbial growth may be necessary.
Accordingly, it is an object of the present invention to provide a process and system for deacidifying NFC juices that minimize the likelihood of undesirable microbial activity during the course of juice processing.
Another object of the present invention is to provide a process and system for deacidifying NFC juices that do not compromise the standard of identity required for such juice products.
It is a still further object to deacidify NFC juices while minimizing the amount of juice that is wasted or becomes otherwise unuseable due to the deacidification process.
A further object of the invention is to provide an improved single strength juice which meets SOI criteria throughout all phases of juice product collection.
It is also an object of the present invention to provide a process and system for deacidifying single strength juices that do not adversely affect the sensory characteristics of the treated juice.